n of iron increases the amount of iron in the blood and
organs.

From these considerations we see how unreliable in pathological cases is
the calculation of the amount of haemoglobin from the amount of iron. We
have been particularly led to these observations by the work of
Biernacki, since the procedure of inferring the amount of haemoglobin
from the amount of iron has led to really remarkable conclusions. For
example, amongst other things, he found the iron in two cases of mild,
and one of severe chlorosis quite normal. He concludes that chlorosis,
and other anaemias, shew no diminution, but even a relative increase of
haemoglobin: but that other proteids of the blood on the contrary are
reduced. These difficult iron estimations stand out very sharply from
the results of other authors and could only be accepted after the most
careful confirmation. But the above analysis shews, that in any case the
far-reaching conclusions which Biernacki has attached to his results are
insecure. For these questions especially, complete estimations with the
aid of the ferrometer of A. Jolles are to be desired.

Great importance has always been attached to the investigation of the
SPECIFIC GRAVITY of the blood; since the density of the blood affords a
measure of the number of corpuscles, and of their haemoglobin equivalent.
It is easy to collect observations, as in the last few years two methods
have come into use which require only a small quantity of material, and
do not appear to be too complicated for practical clinical purposes. One
of these has been worked out by R. Schmaltz, in which small amounts of
blood are exactly weighed in capillary glass tubes (the capillary
pyknometric method). The other is A. Hammerschlag's, in which, by a
variation of a principle which was first invented by Fano, that mixture
of chloroform and benzol is ascertained in which the blood to be
examined floats, _i.e._ which possesses exactly the specific gravity of
the blood[2].

According to the researches of these authors and numerous others who
have used their own methods, the specific gravity of the total blood is
physiologically 1058-1062, or on the average 1059 (1056 in women). The
specific gravity of the serum amounts to 1029-1032--on the average 1030.
From which it at once follows that the red corpuscles must be the chief
cause of the great weight of the blood. If their number diminishes, or
their number remaining constant, they lose in haemoglobin